Over the past few years, there has been a growing concern over global climate change due to an increase in carbon dioxide levels as well as oil supply shortages. As a result, some automobile manufactures and consumers are beginning to have a greater interest in motor vehicles having low emissions and greater fuel efficiency. One viable option is a hybrid electric vehicle (HEV) which allows the vehicle to be driven by an electric motor, combustion engine, or a combination of the two.
Though various features are important to the overall HEV design, the system which stores the energy available for use by the vehicle is a key component. The energy storage system is provided within the HEV to store the energy created by a generator in order for that energy to be available for use by the hybrid system at some later time. For example, the stored energy may be used to drive an electric motor to independently propel the motor vehicle or assist the combustion engine, thereby reducing gasoline consumption.
However, energy storage systems face a variety of design complications, such as over-heating, weight, complexity, ease of incorporation into the vehicle, ease of service, and cost, just to name a few. Additionally, known energy storage systems utilize only a specific and known number of battery packs or modules designed to meet a particular HEV design specification. For example, a battery pack may be specifically designed to provide a specific amount of energy for a 300V vehicle. However, when a different amount of energy is required, such as a 600V system, a different battery pack must be designed to meet the needs of that application. Known battery packs and storage systems can not be utilized or otherwise implemented into different settings without a considerable amount of re-engineering and re-working.
Some known systems allow for separate battery packs to be electrically connected to a separate and distinct control box. Though the independent battery packs may be added to or removed from the overall system, the separate control box is still required. However, because available space for HEV components is at a premium, the inclusion of a separate and distinct control box should be avoided. Additionally, in the event the separate control box fails, the entire energy storage system is unable to function. Thus, there is a need for improvement in this field.
One envisioned area of improvement relates to the safe operation of the HEV, including safety during repair and servicing. In conjunction with the safe operation of a hybrid vehicle, diagnostic tools are included as a part of the control circuitry. Preferably, system failures would be detectable so that repair or service decisions can be made in a timely manner without risking damage to the vehicle or to its components.
While some hybrid system failures can cause damage to hybrid components, other hybrid system failures can cause risks of uncontrolled energy, such as if contactors are closed with the failure not fixed. Some of these failures can only be detected after attempting to enable the hybrid system.
Certain failures can cause further damage if the hybrid system is enabled before the fault is actually repaired, and some of these can come with the risk of uncontrolled energy. Some of these faults require the hybrid system to be enabled (or commanded enabled) to detect, which means the verification of a successful service routine requires an attempt to enable the hybrid system. This attempt, if no service routine was performed, could momentarily re-expose the hybrid system to the fault condition. The disclosed embodiment provides significant confidence to the hybrid system controls that a service routine has been performed and that a subsequent hybrid system enable routine is likely to be successful. The disclosed service disconnect interlock system and method provides an arrangement which allows detection that a repair or service routine has been performed before enabling the hybrid system and therefore avoiding damage to the hybrid components or reducing the risk of uncontrolled energy.